The need for fast, effective and safe transmission of files for application purposes is rapidly increasing. Particularly this is the case in the media industry where it is desirable with transmission of large files composed of different data types, including image information which is very capacity-demanding. Most of the information which is used in the media industry is present digitalized and transmitted in digital form and even though this can take place via existing broadband communications networks, the transmission of source information representing large data volumes, typically several Gbytes, yet becomes an expensive and for the user time-demanding process. Beyond all it is hence desirable to save time and costs in the transmission as well as making the transmission process more simple and efficient, something which will offer an end user great advantages compared with present file transmission systems. In a public data communications network such as Internet, the traffic has only been increasing all the time, something which makes the transmission of large data volumes and large files on Internet both time-consuming and cost-demanding. For large data volumes or extensive documents it hence may be an alternative to make use of courier services or file transmission on dedicated ISDN lines. Even though such measures guarantee a safe transmission, they are yet linked with substantial costs and the use of courier services may in a large number of cases be unsuitable due to the time factor.
In connection with transmission of files data processing the files in connection with a transmission is well-known. Data processing of this kind can typically consist of various forms of compression coding in order to reduce the data volume which shall be transmitted, or measures in order to protect the data which are transmitted against copying. In international published patent publication WO98/44402 there is thus disclosed a method for copying protection of data which are downloaded from a server, typically via World Wide Web, to a client in order to be presented to a user. The transmitted and downloaded data are protected cryptographically by encryption and hashing. The processing to this end may then take place in a network server before transmission on the World Wide Web. Further there is in a paper by Michael Fraase, “Compression pros deliver telecom with SITcom 1.0: Aladdin app offers transparent connection and compression” (MacWEEK, vol. 8, no. 2, 10. Jan. 1994, page 43(2)) disclosed a telecommunication software which automatically can compress files during transmission using the so-called “Stuffit” tool from Aladdin Systems Inc. The users can use this software which is called “SITcomm” for automatically converting files or folder hierarchies to “Stuffit” archives before uploading or for automatically expanding the archives as they are downloaded. SITcomm can also use a so-called toolbox for implementing all connections, file transmissions and emulations.
From U.S. Pat. No. 5,270,805 (Abe et al., assigned to Canon) there is additionally known a data-communication device which generate data as respectively character data and colour image data, these data being divided between respective block areas. The block area for the image data can further be divided into further block areas in correspondence with the image characteristics of the image data. In each case the data transmission takes place blockwise and by means of a conversion device it is determined whether a function is present in the receiver device and the transmitted data in the block areas are converted according to this. This may then imply that if the receiver has no possibilities of processing a colour image, the colour image data will be converted to data which can be processed by the receiver.